The invention relates to a process for determining the backup time of a battery, comprising measuring of the voltage at terminals of the battery, of the charging or discharging current of the battery, computation, from the measured voltage and current values, of the discharge power of the battery and determination of the backup time of the battery in terms of the power.
It is state-of-the-art to determine the backup time of a battery bank, notably a battery bank of an Uninterruptible Power Supply, taking into account the current delivered by the battery, the voltage measured at its terminals, and battery discharge curves obtained experimentally or provided by the battery manufacturer.
In state-of-the-art microprocessor-based systems, the battery discharge curves are recorded, for example in the form of tables, in a memory associated with the microprocessor.
The discharge curves are different for each type of battery and are not always provided in the same form by the suppliers. The curves corresponding to the battery used have to be stored in the device for determining the backup time. This storing requires a large memory capacity. In addition it makes it difficult to take into account ageing of the battery, its actual state of charge and the charge variations in the course of discharging.
The object of the invention is to overcome these shortcomings.